Hey guys, So I've got a Modulus Quantum V. Beautiful bass. I bought it used, so I don't know the exact history of what it's been through. Was made in '08. Sometimes when I turn certain knobs (treble, pickup selection, etc), I hear a crackling sound coming through my amp. I'm wondering if this is a pickup issue (bartolini)? I also have a knob to adjust my mids, but for some reason when I cut the mids, I lose a TON of volume. Is that typical? Shouldn't the volume knob be the only thing affecting the volume?